Vitamin B-12 is the most chemically complex of all the vitamins, and it is essential to the production of red blood cells, the synthesis of genetic materials and the function of your nervous system. Your nervous system is your body's communications system; it includes your brain, spinal cord and peripheral nerves. Deficiencies in vitamin B-12 can result in symptoms related to nerve damage and have also been linked to brain function and dementia, according to the Office of Dietary Supplements.
Cobalamin is another word for vitamin B-12. This is a reference to the presence of a cobalt ion within the chemical structure of the B-12 molecule. B-12 is found in animal-based food sources. Steamed clams and steamed mussels are especially high in B-12, containing 84 mcg and 20.4 mcg, respectively, per 3-oz. serving. Eggs, milk, cheese, meat, fish and poultry also provide B-12. For those over the age of 14, the recommended dietary allowance of B-12 is 2.4 mcg per day. Pregnant women should consume 2.6 mcg daily, and breastfeeding woman should consume 2.8 mcg.
Effects of Deficiency
B-12 deficiency causes megaloblastic anemia, a condition wherein your red blood cell count decreases and abnormally large, immature red blood cells are produced. B-12 also affects your neurological system, which is where brain lesions become a concern. Though the connection between B-12 deficiency and nerve damage has not been completely elucidated, lack of B-12 may affect the outer insulating layer of nerve cells, called the myelin sheath.
According to a study in the February 2009 issue of the "Journal of Neurology, Neurosurgery and Psychology," low B-12 levels are associated with increased severity of white matter lesions in the brain, an effect that may be related to decreased integrity of the myelin sheath. A case study published in the April 2009 issue of the journal "Rinsho Shinkeigaku," or "Clinical Neurology," describes a 39-year-old man whose seizures and multiple brain lesions were improved through B-12 supplementation therapy.
Causes of Deficiency
Because B-12 is found in animal-based foods, deficiencies based on dietary consumption alone are not common. The exception to this is in those who abstain from animal-based foods, such as those who follow a completely vegan diet. More commonly, B-12 deficiencies are due to disorders and conditions that make it difficult for your body to absorb B-12. These include the autoimmune disorder known as pernicious anemia. Older people whose gastrointestinal systems no longer produce enough hydrochloric acid to properly digest foods may also have difficulty obtaining enough B-12 deficiency.